Our local bylaw differentiates between consumer fireworks, which are allowed on private property within the set date parameters, and display fireworks, which require a permit and are governed by various rules. So the Fanshawe Optimists annual show on Victoria Day has a permit, certified staff, and so on while I can buy a box of consumer fireworks the day before and let them off in my backyard with no permit needed.
And as far as letting them off late and waking people up, municipal noise bylaw would apply